Process of treating tussah silk



Patented July 5, 1927.

UNITED STATES PATENT OFFICE.

WHEEL! HELMUT SCHWEITZER, OF HEIDELBERG, GERMANY. I

PROCESS OF TREATING TUSSAH SILK.

1T0 Drawing.

In the treatment of tussah silk fibre it has been customarily boiled off and bleached with weak oxidizing solutions. Until now it has been understood that the fibre would 5 be destroyed or greatly weakened shouid the solution be materially stronger than that customarily employed to' efi'ect the bleaching. I have made the surprising discovery that when tussah silk fibres as well as arti- I ficial silk and vegetable fibres of all kinds are treated with an excess of oxidizing agents over the bleaching agent in use, in a cold solution, the fibres take on a marked lustre and a softer texture and maintain their strength so that they maybe commerciall employed for all uses to which high gra e silk fibre is put. The oxidizing agent for bleachingpurposes has been used in approximately 12% (weight) to the fibre treated in an aqueous solution of 1.5 per cent.

As-an example of my method, 10 0 lbs. of tussah silk fibres preferably before boiling.

off, is treated with 30.1bs. of chlorid of lime dissolved in water, the solution being maintained cold, ice being employed if necessary. The fibre may remainin' the solution forfifteen minutes. They are then washed with water and treated with a neutralizing bath of bisulphide of soda.

The fibres are then washed and then boiled in soap paraflin, etc.', either with or without the addition of a soluble oil.

Application filed June 10, 1924. Serial No. 719,133.

.exceeding that in use for bleaching purposes.

2. The process of treating tussah silk fibres, artlficial silk or other vegetable fibres, which consists in subjecting the fibres to chloride of lime in solution, the roportion of such agent to the fibres being ap proximately 30% by weight, and in water suflicient to dissolve the chloride of lime.-

3. A process in accordance with claim 1 in which the oxidizing bath contains 15% to 20% glycerine to the fibres, by weight.

L 4. A rocess in accordance with claim 1 followe by treatment with boiling soap.

Signed atNew York, in the count of New York and State of New York, t is day of June A. D. 1923.

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